Current Approaches on Viral Infection: Proteomics and Functional Validations

Zheng, Jie; Tan, Boon Huan; Sugrue, Richard; Tang, Kai

Inhibition of PTM signaling pathways could display therapeutic effects to virus infection, since distinctive PTMs could play different roles in virus infectious cycle. For instance, PB1-F2 is encoded by an alternative open reading frame of the PB1 gene. It is a phosphorylated protein predominantly localized in the mitochondria of some virus infected cells to initiate the apoptosis pathway. Also, PB1-F2 is a virulent factor that it could aggravate virus infection by enhancing the secondary bacterial inflammations (Krumbholz et al., 2011) . To explore the innate mechanism of PB1-F2 associated with cellular apoptosis, Mitzner et al. (2009) explored protein kinase C (PKC) mediated-phosphorylation of PB1-F2 by LC-MS/MS and demonstrated the importance of phosphorylation signaling pathways to facilitate apoptosis. Phosphorylation level of PB1-F2 was measured in the presence of inhibitor and activator of PKC, and it is reduced or increased in vitro, respectively. When a mutant virus strain with abrogated PB1-F2 phosphorylation sites was produced to infect primary human monocytes, initiation of cellular apoptosis was impaired and virus propagation was reduced. As another example, the spike protein (S) of SARS is a glycosylation-bearing protein, which is important to viral attachment and subsequent fusion steps. Ritchie et al. (2010) utilized the combination of MALDI TOF MS, negative mode Q-TOF MS, and HPLC to comprehensively study the various types of N-linked carbohydrates associated with the viral spike protein.